graphical user interface

When a person wants to use the computer, they have to somehow interact with it, or use it
(hence the term, "user", which refers to the person using the computer).
A computer's interface is the means by which a user tells the computer what to do.
Of course, a person doesn't only interact with computers, they also "interface" with other tools and machines.
For example, the interface of a stove is the buttons/knobs used to control the temperature; and the interface of a car is the steering wheel, pedals, and other controls.
Stoves have a fairly simple interface, just a few controls, because they can do only one thing.
A car has more options (speed up, slow down, turn, listen to the radio), so it is more complicated.
Computers are even more advanced, and they usually have more flexible means by the user can communicate with it.

There are few computers that lack a keyboard, which is an input device, like the controls on a stove.
On older (personal) computers, the only way for the user to use the computer was through typing commands.
The screen they looked at only showed letters and symbols.
(That way of using the computer is called a character user interface or command line interface.)
A major problem with this method is that new users wouldn't be able to use the computer unless they already knew what to do.
However, with the advent of more powerful computers, the computer can display pictures, or graphics in addition to text.
The user can also use something like a mouse or trackball to move a little picture on-screen (usually in the shape of an arrow) called a cursor.

There are several advantages of a graphical interface over a character interface:

Assuming the user has some basic computer skills (like moving the cursor on the screen using the mouse), they can explore the environment on their own.

The user can see what things they can do, and choose one. This way, they don't have to know what is possible to do and how to do it before they start.

Pictures are easier to comprehend and take less time to process than reading paragraphs of text.

Multiple things can be done at once. If the screen is large enough, the user can work on several things at once, and switch between them at will.

A graphical user interface, or GUI, is simply a method of interacting with a computer that uses pictures and text instead of just text.
Like most things, some GUIs are better than others in certain areas.
A well-made beginner GUI can make it easy for a new user to start using the computer to complete a task, and learn how to do new things on it.
A powerful GUI allows an experienced user to do tasks quickly.
However, in most cases, an interface that is easy for a newbie to use is a hindrance to a power user, and vice versa, which is one contributing factor to OS wars.

Right now you are reading this node through the graphical user interface(GUI) of your browser. It is often described as the look and feel of the computer. Many familiar metaphors are used to describe the interface such as a desktop or seeing applications through windows.

Invented by Xerox in the 70's, and later used by Apple for the Mac. Microsoft came out a couple of years later with many of the same ideas. Elements of the Graphical User Interface include: